Saturday 16 May 2009 19.01 EDT
First published on Saturday 16 May 2009 19.01 EDT

Michael Martin, the Speaker of the Commons, was losing his fight to stay in office last night as Downing Street appeared to abandon support on the eve of a no-confidence motion on his leadership being tabled. If he is ousted, it will be the first time a Speaker has been forced out by a formal challenge since Sir John Trevor was sacked for taking bribes in 1695 during the reign of William of Orange.

Senior MPs of all parties believe that Martin will have no option but to announce, within the next few days, that he is to quit at some point before the next parliament as MPs move to repair the damage inflicted by the expenses crisis. He stands accused of failing to grasp the scale of public anger and rounding on members who question his handling of the affair.

Last night Martin's own former media spokesman, John Stonborough, raised the pressure by accusing him of vetoing reform of the expenses system and exploding with rage when challenged about his own second-home allowance claims. Stonborough suggested that his former boss should now seek a dignified exit, adding: "We should not have to watch the humiliation of him being voted out of office."

Brown has staunchly defended Martin but last night there were signs that this support was ebbing away. "Things are looking difficult for him," said a senior source close to the prime minister. "I don't detect any particular groundswell of support."

Another Brownite minister said the prime minister would not himself intervene, but added: "He is a joke, and he should go."

Tomorrow Tory MP Douglas Carswell will table a motion declaring that "this house has no confidence in Mr Speaker" and calling on him to step down. The motion, signed by about a dozen MPs but backed by many more, says that Martin has "failed to provide leadership relating to hon members' expenses" and demands that a replacement be found to ensure parliament can be "an effective legislature once again".

The Speaker will have to decide whether to risk MPs' wrath by dismissing the motion – or ask the government to find time to debate it. Either way, he will be in such an awkward position that even close friends in the Commons and Lords believe that he may prefer to fall on his sword.

Stonborough, who worked for Martin during a period where the Speaker's own expense claims were headline news, said he had lost his temper at the suggestion that claiming allowances on his Glasgow house did not "look good" while he had a grace-and-favour home in Westminster. The Speaker reacted "extremely violently", Stonborough said, and his officials were scared to challenge his decisions.

Carswell last night called for an urgent contest in parliament, by secret ballot, to install a new Speaker. "I would like there to be a proper open competition so that the public can see that we are selecting the best person to clean up the pigsty," he added.

Those tipped as potential successors include former Labour minister Frank Field, former Tory ministers Sir George Young and David Davis, and Conservative MP John Bercow.

Jo Swinson, the Liberal Democrat MP for East Dunbartonshire, whose constituency includes Martin's home near Glasgow, called for him to go. "The Speaker should have been at the forefront of finding a solution, but has sadly become part of the problem," she said.

Lynne Featherstone, the Liberal Democrat frontbencher, joined calls for him to quit and said she had even urged Liberal Democrat leader Nick Clegg to call for the dissolution of parliament.

David Winnick, one of the Labour MPs who clashed with him last week, said he did not want Martin to be humiliated in a vote. "I know that he is a sensible person. He will be reflecting on his position and I am sure he will come to the obvious conclusion."

Even in his Glasgow North East constituency the mood was hardening against him. Keshia Moweta, a 37-year-old mother of three, said: "It is an absolute disgrace, all of this, and it was him that didn't want all these things published. I would have voted Labour, I always have, but now I don't know."

Moweta's friend, Margaret Meanen, 49, said: "I'd like to get my hands on Michael Martin and have a word with him. To see the state this country is in just now, everybody struggling with the credit crunch, and this is going on. They call it expenses, but it's not expenses, it's living off someone else, it's living off all of us."

While Clegg and Tory leader David Cameron both stopped short of calling for him to go, Clegg suggested it was only a matter of time before a decision was taken.

A spokesman for Martin said merely: "If the Speaker has something to say, he will announce it first to parliament."